Generate the Guid use for php class

< ?php
class   System
{
	function   currentTimeMillis()
	{
		list($usec,   $sec)   =   explode("   ",microtime());
		return   $sec.substr($usec,   2,   3);
	}
}
class   NetAddress
{
	var   $Name   = 'easemarry.com';
	var   $IP   = '69.65.10.199';
	function   getLocalHost()   //   static
	{
		$address   =   new   NetAddress();
		$address->Name   =   $_ENV["COMPUTERNAME"];
		$address->IP   =   $_SERVER["SERVER_ADDR"];
		return   $address;
	}
	function   toString()
	{
		return   strtolower($this->Name.'/'.$this->IP);
	}
}
class   Random
{
	function   nextLong()
	{
		$tmp   =   rand(0,1)?'-':'';
		return   $tmp.rand(1000,   9999).rand(1000,   9999).rand(1000,   9999).rand(100,   999).rand(100,   999);
	}
}
 
class   Guid
{
	var   $valueBeforeMD5;
	var   $valueAfterMD5;
	function   Guid()
	{
		$this->getGuid();
	}
	//
	function   getGuid()
	{
		$address   =   NetAddress::getLocalHost();
		$this->valueBeforeMD5   =   $address->toString().':'.System::currentTimeMillis().':'.Random::nextLong();
		$this->valueAfterMD5   =   md5($this->valueBeforeMD5);
	}
	function   newGuid()
	{
		$Guid   =   new   Guid();
		return   $Guid;
	}
	function   toString()
	{
		$raw   =   strtoupper($this->valueAfterMD5);
		return   substr($raw,0,8).'_'.substr($raw,8,4).'_'.substr($raw,12,4).'_'.substr($raw,16,4).'_'.substr($raw,20).'_'.time();
	}
}
?>